1. Field of the Invention
The present invention relates to a compact and multi-pole waterproof connector which improves the waterproof capability between a connector housing and a plurality of wires connected with terminals.
2. Description of the Related Art
The applicant of the present invention has previously proposed this kind of waterproof connector in Japanese Patent Application No. 10-162521 (not a prior art). FIGS. 1 to 3 show the structure of the waterproof connector. As shown in FIGS. 1 and 2, a connector housing 11 of the waterproof connector 10' has a synthetic resinous inner housing 12 having a plurality of terminal accommodating chambers 13 formed integrally, a synthetic resinous outer housing 17 for fitting the inner housing 12 therein, and a synthetic resinous spacer 28 interposed between the inner housing 12 and the outer housing 17 to retain female terminals 14 accommodated in the terminal accommodating chambers 13 of the inner housing 12.
The inner housing 12 is provided with a box part 12a having upper and lower openings formed on rear sides of the housing 12. In the housing 12, terminal accommodating chambers 13 are defined by a center horizontal wall 12b and upper and lower vertical sidewalls 12c in order to accommodate female terminals 14 in the chambers 13, respectively. On the upper and lower faces of the box part 12a and at the center of the part 12a, respective engagement claws 15 are formed integrally with the housing 12. Further, the housing 12 has flanges 16 integrally formed at respective front ends of the upper and lower faces of the box part 12a. Note, on the front wall of the box part 12a at respective positions corresponding to the terminal accommodating chambers 13, rectangular through-holes 12d are formed for allowing male terminals (not shown) of the mating connector through. In each female terminal 14, a box part 14a is provided, on each side plate thereof, with a pair of press-fitting edges 14b, 14b both folded at the rear part of the terminal 14.
The outer housing 17 comprises an inner wall 17a in the form of a substantially rectangular cylinder, an outer wall 17b in the form of a substantially rectangular cylinder as well, and a bottom wall 17c connected the inner and outer walls 17a, 17b with each other, providing a double-box having an opening at its front end.
Inside the bottom wall 17c, rubber plug accommodating recesses 19 are formed at respective positions corresponding to the terminal accommodating chambers 13, for accommodating waterproof rubber plugs 18'. The bottom wall 17c has wire through-holes 21 formed to allow wires 20 through. Each waterproof rubber plug 18' is in the form of a substantial cylinder having uneven inner and outer peripheral faces, also allowing the wire 20 through.
The spacer 28 comprises a rectangular-cylindrical body part 28a in the form of a generally rectangular cylinder fitted to the outer housing 17, a flange part 28b in the form of a generally rectangular cylinder fitted to the outer housing 17, and a bottom wall 26c of the body part 28c, providing a box having a front section opened.
In the assembled state, the box part 12a of the inner housing 12 is fitted at the interior of the body part 28a of the spacer 28.
Corresponding to the wire through-holes 21 of the outer housing 17, the spacer 28 has also wire through-holes 33 formed in the bottom wall 28c so as to respectively oppose the holes 21 of the outer housing 17 in engagement with the spacer 28. The bottom wall 28c of the spacer 28 is configured so as to retain the rubber plugs 18' at the completion to fit the spacer 28 to the outer housing 17. Before being retained, the rubber plugs 18' have been inserted into the rubber plug accommodating recesses 19 in the bottom wall 17c of the outer housing 17. As shown in FIG. 2, the wires 20 penetrating through the through-holes 21 of the housing 17, respective through-holes 18b of the rubber plugs 18' and the through-holes 33 of the spacer 28, are disposed between the press-fitting edges 14b, 14b in respective pairs, into pressure-connection with the female terminals 14 accommodated in the terminal accommodating chambers 13 of the inner housing 12. With the above arrangement, the terminal accommodating chambers 13 and the wires 20 are waterproofed owing to the rubber plugs 18 and a rubber packing 24 interposed between the outer housing 17 and the spacer 28.
In the bottom wall 17c of the outer housing 17, each rubber plug accommodating recess 19 is provided, on its inlet side, with a reversed conical face (tapered face) 19a. Similarly, the bottom wall 28c of the spacer 28 is provided, about each through-hole 33, with a reversed conical face (tapered face) 28d.
As shown in FIGS. 3A, each rubber plug 18' allowing the wire 20 through is provided, on both axial ends thereof, with conical faces (tapered faces) 18a, 18a. In the dimensional establishment, an inner diameter Rb of the rubber plug 18, i.e., a diameter of the through-hole 18b is equal to or more than a diameter R of the wire 20 (Rb.gtoreq.R). In addition, an outer diameter Ra of the rubber plug 18' is more than a diameter D of the rubber plug accommodating part 19 and there is established a sealing relationship of (Ra-Rb+R&gt;D) in the rubber plug accommodating recess 19.
FIG. 1 shows a temporary engagement condition where the rubber plug 18' is not fitted into the recess 19 completely. The reason of incomplete fitting is to reduce an insertion force in inserting the wires 20 into the rubber plugs 18' at the next-coming formal engagement.
Nevertheless, since the rubber plugs 18' under the above temporary engagement condition is simply pinched between the reversed conical faces 19a of the outer housing 17 and the reversed faces 28d of the spacer 28, there may be occurred a problem of the rubber plugs 18' being detached from the formal position between the reversed conical faces 19a of the outer housing 17 and the same 28d of the spacer 28 due to vibrations, external force, etc.
Additionally, as shown in FIG. 3B, one conical face 18a of the rubber plug 18' comes into "surface" contact with the reversed face 19a of the rubber plug recess 19 of the outer housing 17 while increasing the frictional force therebetween. Therefore, it requires a large insertion force against the plugs 18 to force the rubber plugs 18' into the recesses 19 of the outer housing 17 through the reversed conical faces 28d of the spacer 28. Consequently, there is a possibility of the assembling workability of the waterproof connector 10' being deteriorated.